Scope and content Family papers include letters and postcards from Paul Ehrenfest (1880-1933), to and from Hugo Ehrenfest, to Paul Ehrenfest (1908-2004), to Fritz Ehrenfest, from Tania Ehrenfest (wife or daughter of Paul). Also postcard to Hugo from Paul, signed by Arthur Compton, Albert Einstein, Niels Bohr, and others, 1927; postcard to Fritz Ehrenfest from Niels Bohr and others, 1929; letter from Enrico Fermi, 1938; and two letters from Samuel Goudsmit, 1977. Clippings, especially relating to Paul...